Conventionally, a pneumatic radial tire is generally formed with a tread pattern having a plurality of main grooves extending in the tread circumferential direction in the tread portion, for the purpose of enhancing braking performance, drivability, and wet performance of the tire.
Here, when the tire is mounted on a vehicle, the tire has a portion installed inside (hereinafter, referred to as vehicle-installed inside) and a portion installed outside (hereinafter, referred to as vehicle-installed outside), which are required to have different performance. In light thereof, it is well known in the art to form a tread pattern asymmetric about the tire equatorial plane.
For example, Patent Literature 1 (PTL 1) discloses a technology of providing a large width circumferential groove on the vehicle-installed outside with respect to the tire equatorial plane, to thereby improve drainage performance in a portion to be placed under an increased contact pressure during cornering so as to enhance hydroplaning performance during cornering.